The Research And Simulation Implementation Of The MAC Layer In CR Spectrum Sharing System Based On NS2

Radio spectrum is quite limited compared to the rapid increasation demands of wireless communications for the inefficient fixed spectrum assignment policy. CR (cognitive radio) technology is proposed as a promising concept to increase the spectrum efficiency by exploiting the spectrum opportunistically. So far, most researches of CR have focused on a specific technology or algorithm, but few on system level.In this paper, a simulation platform of CR spectrum sharing system is bulited. The MAC layer protocol of the CR spectrum sharing simulation system based on NS2 is designed and realized, as part of 863 Program's sub-subject. It is verified that the spectrum sharing system which included cognitive MAC function could successfully accomplish communication simulation progress. And through two system simulations which were respectively using game-theoretic distributed channel allocation algorithm and random channel allocation algorithm, it tested several basic system performance indicators and showed the network performance improvement of the system with the game-theoretic algorithm. In addition, a distributed spectrum allocation algorithms based on game theoretical model is proposed and simulated. We ont only verified the advantage of this algorithm in terms of SIR (signal-to-interference ratio) performance but also laid the algorithm foundation for later system simulation.